The present invention relates to a self-looking belt reel-in mechanism, especially for the safety belts of motor vehicles. The mechanism includes a belt-winding spindle that is mounted in a housing and is loaded by a rewinding spring. The belt-winding spindle oomprises a spindle core and a plastic spindle body, at each end of which are disposed two looking members that operate radially between an inner position and an outer position, are adapted to be surrounded by stops on the housing, and bring about a symmetrical quadruple looking. The locking members are coupled by connecting rods that are parallel to the central axis of the belt-winding spindle, are disposed within the cross-sectional area of this spindle, and rotate with the latter. When self-locking is initiated via a system that is sensitive to the movement of the belt and/or of the vehicle, the locking members mesh with the stops on the housing.
A belt reel-in mechanism of this general type is disclosed in German Offenlegungsschrift No. 28 26 286 Seifert et al filed June 15, 1978 and corresponding to U.S. Pat. No. 4,277,036- Seifert et al dated July 7, 1981. In this known mechanism, two separate locking members are disposed on each side of the mechanism. By rotating the pertaining connecting rod, the spring-loaded locking members are moved radially outwardly until they mesh with the toothing of the housing. The force for returning the locking members from the locking position is applied by a spring that directly couples the two locking members.
The drawback of this known belt reel-in mechanism is that a respective locking member must be secured to each end of both of the connecting rods. In addition to requiring a relatively large expenditure for material, this known mechanism also sets high requirements on the precision in determining the position of the locking members relative to the pertaining connecting rods, since a satisfactory operation of the locking members can be assured only if the construction is exactly symmetrical. In addition, the control element, in the form of a control disk, must be disposed next to the locking members, thus requiring an appropriate width for the belt reel-in mechanism. It should also be noted that the return of the locking members via only the springs that connect these members does not assure a synchronous progression of the unlocking, which can adversely affect the functional reliability of the belt reel-in mechanism.
It is therefore an object of the present invention to improve the belt reel-in mechanism of the aforementioned general type in such a way that while keeping the overall width small, the configuration of the locking members is simplified and in particular a synchronous performance during locking and unlocking is achieved.